Tentaculum \Ten*tac"u*lum\, n.; pl. {Tentacula}. [NL. See {Tentacle}.] 1. (Zool.) A tentacle. [1913 Webster] 2. (Anat.) One of the stiff hairs situated about the mouth, or on the face, of many animals, and supposed to be tactile organs; a tactile hair. [1913 Webster]